This is my over engineered chicken farm.
It works on it's with no input from the player. It uses about 18 red stone systems to achieve this. the dimensions are 19 blocks tall, 37 blocks long and 21 blocks wide, making this is easily the most excessive and ridiculous thing I have ever built.
This is probably the most ridiculous and over-complicated chicken farm ever.
The farm is built on a super flat world so it would be easy copy and paste using world-edit or just copy the build from the pictures and my video.
This could likely become more ridiculous, neater and more efficient but it does work so...

The chicken containment chamber has a hopper minecart under it to pick up drops and places them into one of three hoppers: one for chicken, one for feather and one for eggs.
The ones for feathers and chicken go into a chest and are then transported across a hopper line into item sorters. The feathers are moved into a double chest and the raw chicken is moved to a smoker, which empties into a hopper connected to a dropper with a positive feedback loop that spits out the cooked chicken into flowing water, which leads to a bubble elevator pushing the chicken upwards, into flowing water over a hopper which moves it into a double chest.
The item sorter for the eggs empties into a shulker box through a hopper system. Using two comparators and a redstone torch the circuit detects when the box is full. It then breaks the box with a piston and places a new one from a dispenser. When the shulker box is broken, another signal is sent to a signal extender which continues a signal turning off a redstone torch, which allows a looping tick circuit to continuously activate dispensers with harming potions, which are fed by a double chest, each of which in turn is also fed by another double chest full of harming potions.

The full shulker box is transported up a bubble elevator to a hopper which puts it into a dispenser with a positive feedback loop using a comparator to detect when the dispenser has an item in it. The comparator's signal then gets split to a redestone torch keeping a piston active, it deactivates to allow the shulker box to be placed. A comparator then takes over, deactivating the redstone torch until the box is empty.
The signal also deactivates a red stone torch that's preventing the movement of a hopper clock, this torch will deactivate for one cycle of the hopper clock. This then produces a signal that activates the dispenser. The hopper clock is used to create a delay so the piston can retract before the dispenser places the shulker box.
Once the shulker box is placed, a hopper below it empties the shulker box into another dispenser with a positive feed back loop which links to looping tick circuit constantly firing eggs into the enclosure as long as the dispenser has something in it.
Once the shulker box is empty, which is detected by a comparator, a piston breaks the shulker box, which falls into a hopper chain putting the shulker box into a dropper which using a (say it with me now) positive feedback loop, drops the shulker box into a downwards bubble elevator which then flows over a hopper connected to the dispenser that replaces the shulker box for it to be filled again.

TL:DR watch my video https://youtu.be/BSEfnBLCCwo
P.S TL:DR looping afk chicken farm